ABSTRACT Adolescents in underserved, urban communities are disproportionately involved in the juvenile justice system. Youth involvement in the court system is a serious public health concern. In recent years, juvenile justice professionals have begun to supplement traditional efforts aimed at discipline and punishment with an asset- based perspective referred to as positive youth justice (PYJ). The PYJ approach encourages young court participants to build upon their existing strengths, while learning and mastering new life skills through development of pro-social relationships within their peer groups, families, and communities. These core assets are posited to prevent substance use and related risk behaviors and promote successful entry into young adulthood. In the proposed SBIR project, we will adapt and test a two-pronged multi-level intervention for the youth court setting. Youth courts are special diversionary programs for young people who have committed relatively minor offenses; youth who participate in youth courts can avoid the possibility of prosecution and a criminal record. Youth courts have seen tremendous growth over the past two decades and there are now over 1,200 youth courts in the U.S. The first component of the proposed prevention program for youth courts consists of an online training for service providers, designed to promote system-level change within the youth court. The online staff development training will focus on the concepts and practical guidelines of the PYJ model and will train providers to promote pro-social attachment and community involvement for youth participants. The second component is an adaptation of the Life Skills Training (LST) program which will enhance individual-level skills among youth court participants. LST is an evidenced-based drug abuse and violence prevention program that has been extensively tested and documented to be effective by over 30 peer- reviewed papers. LST is strongly aligned with the PYJ model and teaches personal self-management skills, social skills, drug refusal skills, and other life skills needed to successfully navigate developmental tasks, increase resilience, and facilitate healthy psychosocial development. Some youth courts have already independently adopted LST, suggesting that it meets a perceived need and is feasible in this setting. However, LST has never been rigorously adapted, implemented, and tested in the youth court setting. In Phase I we will test the feasibility and acceptability of the online staff training and adapted LST approach in the Youth Court of the District of Columbia (YCDC), the largest youth court in the nation. By intervening with both youth court participants and staff, the proposed intervention can ultimately have a broad impact on risk and protective factors at multiple levels of influence. During Phase II, these intervention components will be tested in a multi- site randomized controlled trial using a sample drawn from the over 1,200 youth courts across the country. The resulting online staff training and youth court materials will provide innovative state-of-the-science tools for use in youth courts and other juvenile justice settings that will have high commercial and public health potential.